Sudden health problems such as sudden cardiac arrest and injuries caused by accidents kill thousands of people and cause permanent injury every year. Fast and competent care to resuscitate such victims of these problems can be essential to positive outcomes in such situations. For example, it is said that the chance of surviving a sudden cardiac arrest falls by ten percent for every minute of delay in providing effective treatment.
Resuscitation treatments for patients suffering from cardiac arrest generally include clearing and opening the patient's airway, providing rescue breathing for the patient, and applying chest compressions to provide blood flow to the victim's heart, brain, and other vital organs. If the patient has a shockable heart rhythm (ventricular fibrillation or pulseless ventricular tachycardia), resuscitation also may include defibrillation therapy. Along with such action, an electrocardiogram (ECG) signal for the patient may be electronically captured, displayed, and monitored, so that rescuers can determine when the patient's heart has returned to normal or near-normal operation, and determine when the heart exhibits a shockable rhythm. About half of patients who suffer ventricular fibrillation (VF) have a recurrence of VF within minutes of successful VF conversion, which may then require reconversion. Patient odds of survival fall with repeated VF recurrence during resuscitation.